Antibridginc apparatus



Dec. 21, 1954 c; s, $TE|NER 2,697,486

ANTIBRIDGING APPARATUS Filed Dec. 28, 1950 IN VEN TOR.

l4 Car/ 61 91: 2 er 1 BY K -W A TI'ORNEY rosewood, ill, assign-.01 to Swift &

ill, a corporation lliinois Application December 78, 95%, Serial No. 263,167

6 Claims. (6i. 159-6) Charles S. Steiner, tConipany, *Ch

The present invention relates to an anti-bridging device for desiccators or the like, of which a flash chamber for drying soap is a typical example. j

The usual procedure with such apparatus is to remove the dried material through a bottom opening in the chamher by gravity. Because of the pressure differential between the interior of the chamber and the atmosphere, the bottom of the chamber is usually formed with a constricted opening leading into a valvewhich will pass the dried material with only minor fluid leakage.

The dried material, which may tend to be sticky and possibly semi-plastic, often builds up about this opening, forming a bridge across the opening and preventing the discharge of any further material until the bridge is broken. ariou devices have been improvised to solve this problem, such as the use of doctor blades, but quite generally they have been ineffective over the extended periods of time in. which such a desiccator operates. The sticky and semi elastic material tends to build up on the doctor blade or other device used for this purpose, and despite its movement, the volume of material disci arged through the constricted opening becomes increasingly smaller.

The principal object of the present invention is to provide an anti-bridging device for such a desiccator, which device not only keeps the discharge throat from backing up with dried material, but which also is selfcleaning so that any material which tends to stick to the device will be regularly detached therefrom.

Additional objects and advantages include: An antibridging device which has inherent safety features to prevent any broken portions of the device from being deposited in other moving parts with resultant damage to those parts; an anti-bridging device which is simple in construction and low in first cost; an anti-bridging device which may be readily adapted for installation with many existing desiccators; and an anti-bridging device which will operate for extended periods of time with little or no care or maintenance.

Further objects and advantages will become apparent from the following description taken in conjunction with the drawings, in which Fig. l is a section of a desiccator showing an embodiment of the present invention therein;

Fig. 2 is an elevational view of the blade of the antibridging device of Fig. 1; and

Fig. 3 is a section taken at line 33 of Fig. l.

The desiccator of Fig. 1 is one of a type well known in the art. it includes a shell, generally it forming a flash chamber, the general configuration of Which is substantially that of a solid of revolution. The lower end of the shell lltl forms a constricted throat 11 through which the dried material is discharged into a star valve, generally 12. The vanes 13 of star valve 12 are slowly rotated about the axis of a shaft 14 by a suitable poweroperated mechanism (not shown). The dried material falling into the space between vanes 13 is carried to a discharge opening lo and from there passes out of the valve.

The anti-bridging device, generally 18, includes a shaft 19 mounted with its axis coincident with the axis of revolution of the exterior of the chamber. The shaft, which is suitably iournaled in the shell 1%, is rotated by an electric motor 253 driving a speed reducer Zl which is connected to the shaft 19. At the other end of the shaft 19 projects an arm 23 carrying the blade 24 of the antibridging device.

The blade consists of a A spring steel rod formed into a U shape, with the projecting ends of the U being secured to the end of arm 23. The portion of the U- shaped rod adjacent the arm 23 acts as a resilient mounting for the lower ends of the rod, which latter ends of the rod actually perform the blade action in breaking up any incipient obstructions at the entrance to throat It will be apparent that as the motor 20 rotates the shaft 19, the blade 24 is moved about a circular bath inside the walls of the shell 10.

Intersecting this path adjacent the unsupported end of the blade 24 are a pair of pins 25 which form abutments or abrupt steps to obstruct the movement of the blade 24 along said path. One end of each of the pins 25 is attached to the wall of the shell It), with the pins projecting inwardly therefrom While the other end of the pins is bent in the direction of movement of the blade 24 within the chamber, which direction of movement is indicated by arrow 26.

As the blade comes in contact with the pins 25, the continued rotation of shaft 19 and arm 23 stresses blade 24, which flexes under the stressing action as indicated in Fig. 2. As the stressing becomes substantial, the blade 24 will sudd'enly slip by pins 25 and commence to vibrate as it seeks a position of rest with respect to arm 23, the vibrations being of a damped oscillatory type wherein the blade moves rapidly back and forth in a plurality of quick movements. The oscillatory movements of the blade not only break up any tendency of the dried m' terial to form a bridge across the opening of throat ill, but also detach any of the dried material that may be tending to adhere to the blade 2d. The action of the blade in this regard is much like the flipping action of ones fingers in attempting to detach a piece of slightly sticky material therefrom.

The number of pins 25 in the illustrated embodiment are two. The number used will depend greatly upon the dimensions of the particular desiccator involved and the gondition of the material which is being discharged thererom.

If, as is often the case, the discharge opening 16 leads into a zone having a substantial pressure differential with respect to the flash chamber, the star valve 12 must be carefully made and fitted so as to provide a minimum of fluid leakage. Any hard foreign material falling into the pockets between vanes 13 of the star valve is likely to injure the seating of the parts of the valve, particularly if the foreign material is of a size too big to be fully received within that pocket. For this reason, it is extremely desirable to prevent any such foreign material from getting into the star valve 12 and damaging an expensive piece of equipment.

The continued stressing of the spring steel rod making up blade 2 may cause the rod to break through fatigue or crystallization or the like. The use of a double rod provides a substantial factor of safety for if one of the rods should break, the other rod will continue to prevent any pieces from falling into the star valve 12. A periodic inspection of the machine will readily show whether or not any fracture of the rod has occurred. Inasmuch as it is extremely unlikely that both sides of the rod would break at the same time, the breaking of one side of the blade gives ample warning that it is in need of replacement.

The foregoing description of a specific embodiment is for the purpose of complying with 35 U. S. C. 112 and should not be construed as imposing unnecessary limitations upon the appended claims. it will be apparent to those skilled in the art that modifications may be made in the disclosed embodiment within the spirit of the appended claims.

I claim:

1. An anti-bridging device for a flash-drying chamber or the like, said device including a resiliently mounted blade within said chamber, means to move said blade along a predetermined path Within said chamber, and means including an abrupt step positioned Within said chamber intersecting said path to alternately stress the resilient mounting for said blade and to suddenly release said stress whereby a damped oscillatory vibration is periodically produced in said blade.

2. An anti-bridging device for a flash-drying chamber or the like, said device including a resiliently mounted blade, means to support the blade within said chamber from one end of the blade with the other end of the blade being unsupported and to move said blade along a predetermined path within said chamber, and a projecting abutment attached to the chamber, said abutment being positioned within the chamber to intersect a portion of said path adjacent the unsupported end of the blade whereby the moving blade is stressed as it intersects said abutment and as it moves by said abutment said stress is suddenly released to produce a damped oscillatory vibration in the moving blade.

3. An anti-bridging device for a flash-drying chamber or the like comprising a blade; power-driven support means for said blade including a shaft mounted axially within said chamber, an arm attached to said shaft and projecting to adjacent the side of the chamber, and power means to rotate said shaft about said axis, one end of said blade being attached to the projecting end of said arm to move along a given path adjacent the walls of the chamber as said shaft is rotated; and a projecting pin forming an abutment intersecting said path adjacent the other end of said blade, at least the portion of said blade adjacent said one end thereof being resilient whereby as the moving blade is stressed as it intersects said abutment it may flex to move by said abutment where upon said stress is suddenly released to produce a damped oscillatory vibration in the moving blade.

4. An anti-bridging device for a flash-drying chamber or the like comprising a blade; power-driven support means for said blade including a shaft mounted axially within said chamber, an arm attached to said shaft and projecting to adjacent the side of the chamber, and power means to rotate said shaft about said axis, one end of said blade being attached to the projecting end of said arm to move along a given path in a predetermined direction adjacent the walls of the chamber as said shaft is rotated; and a pin forming an abutment intersecting one end thereof being resilient whereby as the moving blade is stressed as it intersects said abutment it may flex to move by said abutment whereupon said stress is suddenly released to produce a damped oscillatory vibration in the moving blade.

5. An anti-bridging device for a flash-drying chamber or the like comprising a blade; power-driven support means for said blade including a shaft mounted axially within said chamber, an arm attached to said shaft and projecting to adjacent the side of the chamber, and power means to rotate said shaft about said axis, one end of said blade being attached to the projecting end of said arm to move along a given path adjacent the walls of the chamber as said shaft is rotated; and a pin forming an abutment intersecting said path adjacent the other end of said blade, said blade being formed by a U-shaped bar of resilient material with the two projecting ends of the U being attached to said arm whereby as the moving blade is stressed as it intersects said abutment it may flex to move by said abutment whereupon said stress is suddenly released to produce a damped oscillatory vibration in the moving blade.

6. The combination of a flash-drying chamber, the

. general configuration of at least a portion of said chamsaid path adjacent the other end of said blade, one end her being substantially that of a solid of revolution and an anti-bridging device therefor, said anti-bridging device including a blade means; a power-driven mounting means for said blade means to rotate said blade means about a given circular path within said chamber with the axis of said circular path coincident to the axis of revolution of said solid of revolution, one end of said blade means being resiliently attached to said mounting means, and an abutment attached to said chamber and intersecting said path adjacent the other end of said blade means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 30,516 Ballantine Oct. 23, 1860 864,863 Samuelson Sept. 3, 1907 1,182,612 Wills May 9, 1916 1,925,877 Mitchum Sept. 5, 1933 2,106,295 Cook Jan. 25, 1938 

